Rainbow Rare Earths Ltd (LSE:RBW, OTC:RBWRF) said results have been encouraging from Phalaborwa pilot plant operations in Florida and Johannesburg.
In Florida, rare earth oxide separation is being carried out using a process devised by US-based technical partner K-Technologies.
Rainbow intends to use K-Tech's process to extract rare earths from gypsum dumps at Phalaborwa in South Africa.
Neodymium and praseodymium will be the first oxides to be delivered with dysprosium and terbium to follow, said Rainbow's statement.
In Johannesburg, two of three campaigns have been completed at facilities of the Council for Mineral Technology (Mintek) with around 5.75 kg of mixed rare earth carbonate shipped to K-Tech in five batches to date.
The front-end pilot will start running continuously from the week commencing 15 January 2024, added the statement, with increasing volumes being shipped as 2024 progresses.
This extra processing step does not add any significant capital or operating expenditure to the front-end flowsheet, Rainbow explained, but reduces the quantity of mixed rare earths to be processed in the CIX/CIC circuit by approximately 40%, with resultant capital and operating cost benefits.
George Bennett, chief executive, commented: "Whilst we have experienced some delays from the original timetable this has in no way affected the integrity of the process flowsheet which is progressing as planned.
“During this time, we have continued with front-end plant optimisation work to deliver the most efficient final flowsheet for commercial operations, as well as ongoing shipments of mixed rare earth carbonate to K-Tech.”